Catheter-advancement actuated needle retraction system

ABSTRACT

A catheter-advancement actuated needle retraction system is disclosed herein. The invention includes a generally hollow barrel that houses a needle hub, which can include a flashback chamber. A needle is affixed to the distal end of the needle hub and is aligned to extend through an opening in the distal end of the barrel. The needle extends through a catheter hub and catheter affixed to the catheter hub. A spring is disposed in the barrel lumen to cooperate with the needle hub to urge the needle hub toward the proximal end of the barrel. A latch actuator is releasably engaged with the catheter hub. A latch which cooperates with the latch actuator is movable between one position which maintains the needle hub adjacent to the distal end of the barrel and a second position allowing the spring to urge the needle hub to the proximal end of the barrel. A mechanism may be provided to cushion the needle hub as it contacts the proximal end of the barrel by the force of the spring.

This application is a continuation of application Ser. No. 08/483,428,filed Jun. 7, 1995, now abandoned, which is a division of applicationSer. No. 08/400,150, filed Mar. 7, 1995, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates in general to an intravenous ("IV") catheter andintroducer needle assembly having a novel needle retraction system.

IV catheters are used to provide fluid to or withdraw fluid from apatient. In order to properly place an IV catheter in a patient's vein,a sharp introducer needle must be used to puncture the skin, tissue andvein wall to provide a path for placement of the catheter in the vein.Typical IV catheters are "over-the-needle" catheters where the catheteris coaxially placed over the needle. The catheter thus rides with theneedle through the skin, tissue and vein wall and into the patient'svein. When the needle pierces the vein, blood will "flashback" into theneedle. Thus, once the medical technician observes this "flashback" ofblood, the medical technician will know that the catheter and needlehave been inserted in the vein. The needle can then be withdrawn fromthe patient and the catheter can be advanced further into the vein.

In recent years, there has been great concern over the immediatedisposal of needles after use. This concern has arisen because of theadvent of currently incurable and fatal diseases, such as AcquiredImmune Deficiency Syndrome ("AIDS"), which can be transmitted by theexchange of body fluids from an infected person to another person. If aneedle has been used to place a catheter in the vein of an AIDS infectedperson, the needle is a vehicle for the transmission of the disease.Thus, it is extremely important for a medical technician to properlydispose of the needle to avoid a needlestick with the contaminatedneedle. Unfortunately, in certain medical environments, such asemergency situations, needlesticks with a contaminated needle can occurif the contaminated needle is not somehow covered immediately after use.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide a safety catheterand needle introducer assembly where the needle can be coveredimmediately after use.

It is another object of this invention to provide a safety catheter andneedle introducer assembly that is easy to use.

The catheter-advancement actuated needle retraction system of theinvention comprises a generally hollow barrel, a needle slidablydisposed in the barrel so the sharp distal tip of the needle caninitially extend beyond the distal end of the barrel and then can beretracted completely into the barrel, a needle hub, which may include aflashback chamber, fixed to the proximal end of the needle, a springassociated with the needle hub and the barrel, a movable latch forinitially maintaining the needle hub adjacent to the distal end of thebarrel, and an actuation device that can cooperate with the latch toallow the spring to force the needle hub and the needle toward theproximal end of the barrel.

The above and other objects and advantages of the invention will beapparent upon consideration of the drawings and the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiments are illustrated in the drawings in which likereference numerals refer to like elements and in which:

FIG. 1 is a perspective view of a first embodiment of this inventionwith the catheter advanced from the distal end of the barrel and theneedle in the fully extended position prior to retraction into thebarrel;

FIG. 2 is a perspective view of the first embodiment of the inventionsimilar to that shown in FIG. 1 but with the catheter removed from theintroducer needle assembly for clarity;

FIG. 3 is a side view in cross-section of the first embodiment of thisinvention prior to insertion of the needle and catheter into a patient;

FIG. 4 is a side view in cross-section of the first embodiment of thisinvention with the needle in the retracted position after the catheterhas been advanced into a patient;

FIG. 5 is a side view similar to FIG. 3 but showing a variation of thefirst embodiment of the invention with a different latch actuator;

FIG. 6 is a perspective view of a second embodiment of this inventionwith the catheter advanced over the needle prior to retraction of theneedle into the barrel;

FIG. 7 is a side view in cross-section of the second embodiment of thisinvention prior to insertion of the needle and catheter into a patient;

FIG. 8 is a side view in cross-section of the second embodiment of thisinvention with the needle in the retracted position after the catheterhas been advanced into a patient;

FIG. 9 is a side view in cross-section of a third embodiment of thisinvention prior to insertion of the needle and catheter into a patient;

FIG. 10 is a side view in cross-section of the third embodiment of thisinvention with the catheter advanced over the needle prior to retractionof the needle into the barrel;

FIG. 11 is a cross-sectional view of the third embodiment of thisinvention taken along line 11--11 in FIG. 10;

FIG. 12 is a cross-sectional view of the third embodiment of thisinvention taken along line 12--12 in FIG. 10;

FIG. 13 is a perspective view of the needle hub used in the thirdembodiment for this invention;

FIG. 14 is a perspective view of the proximal end of the needle hubshown in FIG. 13;

FIG. 15 is a side view in cross-section of an alternative embodiment ofthe catheter hub and distal portion of the latch actuator of thisinvention;

FIG. 16 is a side view in cross-section of a fourth embodiment of thisinvention for use with a winged catheter;

FIG. 17 is a perspective view of a fifth embodiment of this inventionprior to insertion of the needle and catheter into a patient;

FIG. 18 is an exploded perspective view of the fifth embodiment of thisinvention;

FIG. 19 is a perspective view of the rear of the camming rod and of thefront and bottom of the barrel of the fifth embodiment of thisinvention;

FIG. 20 is a side view in cross-section of the distal portion of thefifth embodiment of the invention prior to insertion of the needle andcatheter into a patient;

FIG. 21 is a side view in cross-section of the distal portion of thefifth embodiment of the invention after the catheter has been advancedover the needle and the needle is being withdrawn into the barrel;

FIG. 22 is a perspective view of the proximal end of the camming rod andthe keylatch of the fifth embodiment of the invention, with the keylatchshown at the extreme proximal end of the camming rod in phantom;

FIG. 23 is a perspective view similar to FIG. 22 but showing a variationof the camming rod and the keylatch; and

FIG. 24 is a perspective view of another embodiment of the keylatch.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the catheter-advancement actuated needle retractionsystem of this invention can be seen generally in FIGS. 1 through 5.This system includes a catheter 10, a catheter hub 11, a needle 20, aneedle hub 21, which can include a flashback chamber, a barrel 30 forshielding the sharp distal tip of needle 20 after use, a spring 40, amovable latch 50 and a latch actuator 60. Barrel 30 can include acontoured ergonomic handle 90 for ease of gripping.

Referring to FIGS. 3 and 4, barrel 30 is generally hollow and has aninner longitudinally extending wall 31 that divides barrel 30 into twodistinct chambers. This wall 31 serves to guide needle hub 21 withinbarrel 30 as needle hub 21 and needle 20 are retracted into barrel 30under the force of spring 40. In addition, wall 31 helps to avoidinterference between latch actuator 60 and needle hub 21 duringoperation of the mechanism. Of course, it is not essential to have wall31 and two distinct chambers. However, this configuration facilitatesreliable retraction of needle 20 into barrel 30. Wall 31 should define acut out portion to allow placement of a latch 50 therein. The purposeand description of latch 50 will be provided hereinafter.

First chamber 32 houses needle hub 21, spring 40 and needle 20 when itis retracted into barrel 30. First chamber 32 should be long enough sothat when needle hub 21 is completely retracted into barrel 30 so needlehub 21 is adjacent to the proximal end of barrel 30, the sharp distaltip of needle 20 does not extend beyond the distal end of barrel 30. Thedistal end of first chamber 32 includes an opening to allow needle 20 toextend beyond the distal end of barrel 30. The distal end of barrel 30includes a neck 38. Neck 38 has a proximal end around which spring 40can be located and a distal end around which catheter hub 11 can beplaced. Alternatively, instead of forming the distal end of barrel 30 tohave neck 38, needle hub 21 could include a distal neck substantially inthe shape of the distal portion of neck 38. This distal neck of needlehub 21 would then extend through an opening in the distal wall of barrel30 sized to fit that portion of needle hub 21. The portion of needle hub21 proximal to its distal neck would have to include a cut out portionor otherwise be sized to accommodate spring 30. Spring 40 would thensurround that portion of needle hub 21 and abut the distal wall aroundthe opening formed in barrel 30 for the distal neck of needle hub 21.

Second chamber 33 houses latch actuator 60 and should be sizedaccordingly. The distal end of second chamber 33 includes an openingthrough which latch actuator 60 can extend.

Needle 20 is attached at its proximal end to needle hub 21. Needle hub21 preferably includes a flashback chamber to collect the blood that"flashes back" through needle 20 when the sharp distal tip of needle 20pierces a patient's vein. The combined length of needle 20 and needlehub 21 should be less than the internal length of barrel 30. In thisway, and as discussed above, when needle 20 and needle hub 21 areretracted into first chamber 32 of barrel 30, the sharp distal tip ofneedle 20 will not be exposed outside of barrel 30 but instead will besafely housed inside.

Spring 40 is disposed about the proximal portion of neck 38 between thedistal end of needle hub 21 and the distal wall of barrel 30. Althoughspring 40 is preferably placed coaxially about the proximal portion ofneck 38, spring 40 could also be located adjacent to neck 38 or in someother non-coaxial arrangement with the proximal portion of neck 38. Whenneedle 20 is in the extended position, the distal end of needle hub 21is adjacent to the distal wall of barrel 30. Spring 40 is placed incompression in this arrangement. Thus needle hub 21, and needle 20, willbe urged away from the distal end of barrel 30 by spring 40 if needlehub 21 is not held in position. Although this is the preferredorientation for spring 40 in this embodiment as well as the remainingembodiments of this invention, it is to be understood that spring 40could be located between and connected to the proximal end of barrel 30and the proximal end of needle hub 21. By placing spring 40 in tensionin this arrangement, a biasing force is provided to needle hub 21 tourge needle 20 toward the proximal end of barrel 30. This arrangementcan also be used with the other embodiments of this invention.

Latch 50 serves to maintain the position of needle hub 21 adjacent tothe distal end of barrel 30 during insertion of catheter 10 into apatient. Latch 50 is secured to barrel 30 such that it pivots about pin55. Latch 50 includes two generally parallel teeth 51 and 52 extendingin opposite directions from either end of the body of latch 50. Firsttooth 52 is configured to engage the proximal end of needle hub 21 tomaintain the position of needle hub 21 adjacent to the distal wall ofbarrel 30. Latch 50 may be pivoted in a counterclockwise direction asshown in FIGS. 3 and 4 to allow spring 40 to urge needle hub 21 andneedle 20 away from the distal wall of barrel 30 to retract needle 20into first chamber 32 of barrel 30 and thus shield the sharp distal tipof needle 20 after use.

Latch actuator 60 is used to pivot latch 50 away from engagement withneedle hub 21. Latch actuator 60 has a first shoulder 61 at its proximalend that engages with second tooth 51 as latch actuator 60 is moved inthe distal direction to rotate latch 50 in the counterclockwisedirection as seen in FIGS. 3 and 4. Latch actuator 60 has a secondshoulder 62 at its distal end that engages catheter hub 11. As seen inFIGS. 1 and 2, second shoulder 62 can take the form of a semi-circularclip that connects to catheter hub 11 adjacent to the proximal flange ofcatheter hub 11. Once needle 20 and catheter 10 have properly engaged apatient's vein, the health care worker can advance catheter 10 orretract barrel 30 to remove needle 20 from catheter 10. As a result ofthis motion, latch actuator 60 moves distally with respect to barrel 30since second shoulder 62 of latch actuator 60 is still held to catheterhub 11. Shoulder 61 thus moves toward the distal wall of barrel 30 andengages second tooth 51 to pivot latch 50 away from needle hub 21.Spring 40 will then cause needle 20 to be retracted into barrel 30. Atthis point, second shoulder 62 can be moved away from contact withcatheter hub 11. The needle assembly can then be completely withdrawnleaving catheter 10 in place.

As an alternative embodiment, latch actuator 160 can be connected tocatheter hub 11 as shown in FIG. 5 by any standard means. In addition,an enlarged bead 161 or some other protuberance at the proximal end oflatch actuator 160 can be used instead of a shoulder to engage secondtooth 51 of latch 50.

A second embodiment of latch actuator 260 is shown in FIGS. 6 through 8.In that embodiment, latch actuator 260 comprises a wire formed into twolongitudinally extending rails 269 and a push off tab 268.Alternatively, latch actuator 260 could include only one longitudinallyextending rail 269. Push off tab 268 is formed such that it snaps overcatheter hub 11 and can be easily removed from catheter hub 11 oncecatheter 10 is properly placed in a patient's vein. Longitudinallyextending rails 269 extend into barrel 230 in chambers 231 and 232 sothat at least one of the longitudinally extending rails 269 willinteract with latch 250 to disengage latch 250 from needle hub 221 toallow needle 20 to retract into barrel 230.

In the second embodiment of this invention, latch 250 pivots about point251 in a cantilever fashion and is biased away from needle hub 221.Latch 250 includes an enlarged foot 252 than engages needle hub 221.Foot 252 is held in slot 225 of needle hub 221 by one of thelongitudinally extending rails 269. See FIG. 7. Thus, when needle 20 iswithdrawn from catheter 10 or when catheter 10 is advanced further intoa patient's vein, the longitudinally extending rail that holds foot 252in slot 225 will move away from engagement with foot 252. With nothingholding foot 252 in slot 225 against its bias, foot 252 will move awayfrom slot 225. This will allow spring 40 to urge needle hub 221 and thusneedle 20 away from the distal end of barrel 230.

FIGS. 7 and 8 also show another configuration for the proximal end ofbarrel neck 238 and the distal end of needle hub 221. As can be seen, acut out exists in the proximal end of barrel neck 238 and the distal endof needle hub 221 to house the ends of spring 40.

As an alternative to push off tab 268 shown in the embodiment of FIGS. 6through 8, an automatic release mechanism such as shown in FIG. 15 canbe used. In the version of FIG. 15, each longitudinally extending rail269 is formed to have a bulbous distal tip 201 and an outwardlyextending shoulder 202 along its distal portion proximal of bulbousdistal tip 201. These bulbous distal tips 201 are dimensioned such thatthey can fit within the proximal end of catheter hub 211. Each bulbousdistal tip 201 fits inside a cut out portion 205 on the inside ofcatheter hub 211. Shoulders 202 abut the proximal flange of catheter hub211. With needle 20 extending through catheter 210, rails 269 are biasedinto engagement with cut out portions 205 of catheter hub 211. Whencatheter 210 is advanced to actuate the latch, needle 20 is withdrawnfrom catheter 210 and catheter hub 211 thus removing the biasing forcefor rails 269. Bulbous distal tips 201 of rails 269 thus lose contactwith cut out portions 205 of catheter hub 211 allowing catheter 210 andcatheter hub 211 to be automatically removed from the introducer needleassembly. It is to be understood that the automatic release mechanismshown in FIG. 15 could be adapted for use with all of the embodiments ofthe invention disclosed herein.

In the third embodiment of this invention shown in FIGS. 9 through 14,latch 350 is affixed to the outer surface of needle hub 321. Latch 350has an upwardly extending body 353 that is biased away from needle hub321. Latch 350 also has a portion which descends from body 353 in agradual ramp 354 and another portion which ends in abutments 355. Theseabutments 355 engage with shoulders 331 formed in the inner wall ofbarrel 330. Shoulders 331 are shown in FIGS. 11 and 12 and are inphantom in FIG. 13.

Latch actuator 360 is formed with a pigtail 361 at its proximal end.Needle hub 321 is oriented in barrel 330 so that latch actuator 360extends over ramp 354 of latch 350. As needle 20 is removed fromcatheter 10, latch actuator 360 passes over ramp 354. When pigtail 361passes over ramp 354, latch 350 is urged toward needle hub 321 so thatabutments 355 disengage from shoulders 331. This allows spring 40 tourge needle hub 321 away from the distal wall of barrel 330.

The proximal end of needle hub 321 can also include a plurality oflongitudinally extending tines 80. Tines 80, which may be collapsible,cushion needle hub 321 when it is forced against the proximal wall ofbarrel 330. These tines 80 could also be incorporated on the needle hubsin all of the different embodiments of this invention as well as indifferent safety catheter systems that use a spring to retract theneedle inside the barrel, such as described in U.S. Pat. No. 4,747,831.

A variation of the first embodiment of this invention is shown in thefourth embodiment of FIG. 16. The catheter-advancement actuated needleretraction system of this invention can be used with a butterfly typecatheter 400 having an extension tube 490 connected thereto tofacilitate the infusion of I.V. fluids into the patient. In thisembodiment, a tab 460 is affixed to extension tube 490 and extends intobarrel 430 through a slot 480 formed in the side wall of barrel 430. Asbarrel 430 is moved away from catheter 400 to remove needle 420, tab 460slides distally along slot 480 to actuate latch 450. Tab 460 can beconnected to extension tube 490 via a removable clip. Alternatively, tab460 can be formed with a score line or some other means for weakeningthe connection between tab 460 and extension tube 490 to allow tab 460to be removed easily therefrom.

In the fifth embodiment of this invention, shown in FIGS. 17 through 24,a camming rod 569 is used to move a keylatch 550 out of engagement withneedle hub 521. Keylatch 550 includes a keyhole 555 therein having alarger portion 555a and a smaller portion 555b. Keylatch 550 rides alongrail 595 of camming rod 569. Rail 595 is arranged to allow either largerhole 555a or smaller hole 555b to be aligned with the longitudinal axisof camming rod 569.

Camming rod 569 rides along the bottom of barrel 530 so that push offtab 568 is either adjacent to the distal end of barrel 530, as shown inFIGS. 17 and 20, or is removed therefrom as shown in FIG. 21. The distalend of camming rod 269 includes bulbous distal tips 501 which functionin the same manner as the automatic release mechanism shown in FIG. 15.

Keylatch 550 is disposed inside barrel 530 about needle hub 521. Whencamming rod 569 is in the position shown in FIGS. 17 and 20, smallerhole 555b engages needle hub 521 to hold it adjacent to the distal endof barrel 530. In this position, spring 540 is held in compressionbetween keylatch 550 and the proximal end of needle hub 521. After thetip of needle 20 and catheter 210 have been inserted into a patient,push off tab 568 can be pushed forwardly to advance catheter 210 furtherinto the patient. This motion advances camming rod 569 forwardly withrespect to barrel 530. This in turn causes keylatch 550 to be moved tothe side because of the orientation of rail 595 until larger hole 555ais aligned with the longitudinal axis of camming rod 569. Larger hole555a has a sufficiently large diameter to allow needle hub 521 to passtherethrough. Thus when camming rod 569 is advanced, larger hole 555a ofkeyhole latch 550 becomes aligned with needle hub 521 to allow spring540 to urge needle hub 521 to the proximal end of barrel 530 and retractneedle 20.

Keyhole latch 550 and rail 595 can have different orientations, as shownin FIG. 23, as long as keylatch 550 maintains needle hub 521 adjacent tothe distal end of barrel 530 against the force of spring 540, andkeylatch 550 can be selectively moved to allow needle hub 521 to bemoved to the proximal end of barrel 530 by the force of spring 540. Inthe version shown in FIG. 23, rail 595 is oriented to move keylatch 550vertically. In this version keyhole 555 has larger opening 555a beneathsmaller opening 55b so that as rail 595 is moved forwardly, largeropening 555a will be moved upwardly into alignment with needle hub 521.

As shown in FIG. 24, keylatch 550 can include a pushing surface 559 thatextends outside of barrel 530 and a cutout portion 560 that defines abreakable pin 561. This embodiment allows keylatch 550 to be activatedto retract needle 20 into barrel 530 without the need to advance cammingrod 569.

Each of these embodiments achieves the desired goal of providing asafety catheter and needle introducer assembly where the needle can becovered after use and which is easy to use.

What is claimed is:
 1. A catheter and needle introducer assembly,comprising:a barrel having a length defining a barrel lumen and having aproximal end and a distal end, the distal end defining a distal wallwith an opening extending therethrough, the barrel including a sidewallwith a slot formed therethrough and extending along at least a portionof the length of the barrel; a catheter having a proximal end and adistal end; a catheter hub affixed to the proximal end of the catheterand located adjacent to the distal end of the barrel; an extension tubein fluid communication with the catheter; a needle having a sharp distaltip and a proximal end; a needle hub having a proximal end and a distalend affixed to the proximal end of the needle, the needle hub beingdisposed in the barrel lumen such that the sharp distal tip of theneedle initially extends distally of the distal wall of the barrelthrough the opening coaxially within the catheter; a spring cooperatingwith the needle hub to urge the needle hub toward the proximal end ofthe barrel; a latch associated with the barrel to initially contact andhold the needle hub adjacent to the distal end of the barrel and to bemovable to a position away from contact with the needle hub; and a tabaffixed to the extension tube and extending through and slidablyreceived in the slot in the barrel to engage the latch when the catheteris moved distally with respect to the barrel.
 2. The catheter and needleintroducer assembly of claim 1 wherein the tab is removably connected tothe extension tube.